Resistance testing

Resistance testing is recommended at the time of HIV diagnosis and to guide selection of an initial and subsequent ARV regimens. Even if testing is not possible at the time of diagnosis, it is extremely useful to store a blood sample, drawn as soon as possible after the diagnosis of HIV is made, to have available for later use.

The ability of resistance assays to detect transmitted resistant virus is greatest during primary infection and lessens as the time from infection progresses. This is because of the evolution in viral population. Thus, whenever possible, blood samples should be taken early in infection and stored for later use.

Resistance testing can help guide the selection of an ARV regimen at certain times during the course of infection. It can be used:

  • In acute HIV infection, as close as possible to the time of diagnosis.
  • For baseline testing of chronically infected people at the time of entry into care.
  • In some cases when re-infection is suspected.
  • Before an initial ARV regimen is chosen, if treatment after the first test is deferred.
  • When there is a suboptimal response to therapy.
  • When previously suppressed viral load becomes detectable.
  • During pregnancy, prior to ARV initiation or if viral load is detectable.

The drawbacks of resistance testing include:

  • Complexity of interpreting and applying results.
  • Interpretation of results is not precise and results are subject to change.
  • Availability of laboratories with required capabilities, standardisation, and quality control.
  • Lack of accuracy across all subtypes.
  • Inability of most assays to detect minority virus populations.
  • Cost.
  • Time involved to receive results.

Various treatment guidelines have different recommendations on when to test. For the BHIVA and US DHHS guidelines on this subject, see the section Treatment guidelines.

Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.